JP4269116B2 - Mold shape design device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional product manufacturing method and a three-dimensional product manufacturing apparatus for parts, products, models, and the like, and more particularly, to a three-dimensional product manufacturing method and a manufacturing apparatus that require high strength and rigidity.
[0002]
[Prior art]
A technique for quickly and easily materializing computer three-dimensional data is called rapid prototyping (RP). A photo-fabrication method in which a liquid synthetic resin is exposed to cause a photochemical reaction to be partially solidified, or a selective laser sintering method (SLS method) in which a powder is irradiated with a laser beam to be partially solidified. Is well known. The details of rapid prototyping are described in, for example, Takeo Nakagawa and Yoji Marutani “Multilayer Modeling System” (Industry Research Committee).
[0003]
Generally, in rapid prototyping, a large number of thin layers having a thickness of 10 μm to 1 mm are stacked and formed, so that even complicated shapes can be created without changing the process. Taking advantage of this feature, for example, if rapid prototyping is introduced into a design work that optimizes the shape of a part while repeating an experiment, an experimental model can be manufactured at any cost from 3D CAD data at any time. become. In other words, design work can be shifted to a form centered on three-dimensional CAD, and so-called concurrent can be achieved.
[0004]
In addition, it is possible to realize custom design production that increases the added value of the product by producing a single product according to demand by leaving the design of the product to the user.
[0005]
However, conventional rapid prototyping materials do not necessarily have sufficiently high strength and rigidity to withstand use as a product casing or experimental model.
[0006]
To solve these problems, there is a method of post-processing the shaped object and replacing the rapid prototyping resin material with metal. Often used is a method called disappearance model casting (investment casting). In this method, a model formed by rapid prototyping is embedded in foundry sand, and molten metal is poured from above. Then, the shaped object is decomposed by the heat into gas or melted and soaked into sand, and the shape of the shaped object is replaced with metal as it is.
[0007]
Japanese Patent Laid-Open No. 7-195141 discloses a method of manufacturing a model by an optical modeling method, immersing the model in a ceramic slurry, sprinkling refractory particles, and then melting and removing the model to quickly make a mold. Is shown.
[0008]
In addition, a method is also used in which a metal powder such as stainless steel is formed as a material of the SLS method and finished by infiltrating copper or the like with a resin or the like.
[0009]
According to these methods, it is possible to make a shaped object having higher strength and rigidity than a shaped object made only of a resin material.
[0010]
Japanese Patent Application Laid-Open No. 10-156514 discloses that a three-dimensional shape body is formed with an optical modeling apparatus using a metal powder having a surface coated with a thermoplastic resin as a raw material, and a sand is applied thereto to form a shell. A method of impregnating a shaped body with molten metal is shown.
[0011]
[Problems to be solved by the invention]
All of the conventional techniques require large-scale facilities for post-processing. In the vanishing model casting method, equipment for heating and melting the metal at a temperature of 600 ° C. or higher is required. Moreover, in the SLS method using a metal powder, the equipment for infiltration which keeps a high temperature for a long time and the pressurization and pressure reduction equipment at the time of making a resin penetrate | infiltrate a modeling thing are required.
[0012]
These facilities required considerable skill to operate. It is conceivable to use facilities owned by other companies, but in that case, it takes time for logistics, and the simplicity and speediness characteristic of rapid prototyping are impaired.
[0013]
Moreover, in the said prior art, the precision and surface roughness of a molded article were inferior. Therefore, when a model with a smooth surface or a model with high accuracy is required, a great deal of labor and time are required for finishing, and there is still a problem in terms of simplicity and speed.
[0014]
An object of the present invention is to provide a three-dimensional product manufacturing method and a three-dimensional product manufacturing apparatus that can rapidly and easily manufacture a three-dimensional product having high strength and rigidity, excellent accuracy, and surface roughness by utilizing rapid prototyping. is there.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a mold manufacturing process in which a mold is made of a thermoplastic material, and an easily fused gold melted at a temperature lower than the softening point of the thermoplastic material is poured into the mold and solidified for casting. 3D product manufacturing method including easy fusion gold casting process to make product and mold removing process of dividing mold and removing casting product as target 3D product In the mold shape design apparatus for supporting the mold shape creation in the above, an offset mold creation means for creating the outer shape of the mold by offsetting all or part of the shape of the target three-dimensional product outward is provided. In this way, if a mold is made of a thermoplastic material, and an easily fused gold melted at a temperature lower than the softening point of the thermoplastic material is poured into the mold and solidified into a cast product, rapid prototyping is utilized, which is high. A solid product having excellent accuracy and surface roughness as well as strength and rigidity can be quickly and easily manufactured.
[0016]
The thermoplastic material is a resin material or a composite material of resin, and the mold manufacturing process is a selective laser in which the powder of the thermoplastic material is partially sintered to form a thin layer and the thin layer is stacked to form the mold. A sintering method (SLS method) modeling step can be included. In this case, a three-dimensional product having a complicated three-dimensional shape can be manufactured without making the process complicated by utilizing a commercially available modeling apparatus.
[0017]
When the thermoplastic material is a composite material including a resin and inorganic material beads, it is possible to suppress the deformation of the mold that occurs during casting and to manufacture a highly accurate three-dimensional product. If the thickness of the mold is reduced, the time for cooling the mold in which the easy fusion gold is cast is shortened. In this sense, a three-dimensional product can be manufactured quickly.
[0018]
Desirably, the thermal conductivity of the inorganic material beads is larger than the thermal conductivity of the resin. This is because the time required for cooling the mold in which the easy fusion gold is cast can be shortened and a three-dimensional product can be manufactured more rapidly.
[0019]
In any three-dimensional product manufacturing method, the mold manufacturing process can include a mold smoothing process for smoothing the surface of the mold. Since the surface of the mold needs to be smoothed only once, the trouble of smoothing the surfaces of a plurality of three-dimensional products having the same shape can be saved, and a large number of three-dimensional products with smooth surfaces can be produced quickly and easily.
[0020]
The mold removing step may include a cast product smoothing step of smoothing the surface of the cast product. In general, since a concave portion that is difficult to reach in the smoothing process of the mold becomes a convex part in the smoothing process of the cast product, a three-dimensional product having a smooth all surface can be manufactured quickly and easily.
[0021]
The mold manufacturing process includes a process of forming a flow path for heat exchange inside the mold, and the easy fusion casting process includes a mold cooling process of circulating a cooling fluid through the flow path to cool the mold. May include. With this method, it is possible to quickly manufacture a three-dimensional product having a high strength and being difficult to be deformed by creep, by shortening the time for cooling the mold in which the easy fusion gold is cast, improving the material characteristics of the easy fusion gold.
[0022]
The easy fusion gold casting step may include a reinforcing material installation step in which a reinforcing material is placed in the mold before pouring the easy fusion gold into the mold, and a three-dimensional product having high strength and rigidity can be manufactured.
[0023]
The mold manufacturing process includes a process of forming a flow path for heat exchange inside the mold, and the easy-fusion gold casting process heats the mold by circulating a heating fluid through the flow path. Can also be included. It is possible to avoid defects caused by non-uniform solidification of easily fused gold in contact with a normal temperature reinforcing material, and reliably manufacture a three-dimensional product having high strength and rigidity.
[0024]
If a metal piece having a melting point higher than that of the easily fused gold is used as the reinforcing material, a three-dimensional product having higher strength and rigidity can be manufactured.
[0025]
In the case of including a reinforcing material forming step in which a metal powder having a melting point higher than that of the easily fused metal is partially sintered to form a thin layer and the thin layer is stacked, the filling rate of the reinforcing material with respect to the mold volume The three-dimensional product having particularly high strength and rigidity can be manufactured.
[0026]
By including a reinforcing material infiltration step in which metal is infiltrated into the porous reinforcing material, a three-dimensional product having particularly high strength and rigidity can be quickly and easily manufactured using a commercially available modeling apparatus.
[0027]
If the mold removal process includes the process of applying impact or vibration to the mold to separate the mold and the cast product, the three-dimensional product stuck in the mold can be easily taken out, and a three-dimensional product with a complicated and fragile shape can be obtained. Simple and reliable production.
[0028]
Including an offset mold shape creation step in which the shape of the mold is created by offsetting all or part of the shape of the target three-dimensional product can suppress the deformation of the mold during casting and manufacture a highly accurate three-dimensional product.
[0029]
A mold shape design device equipped with an offset mold creating means for offsetting all or part of the shape of the target three-dimensional product outward to create the outer shape of the mold, or aligning the molds divided into a plurality of each other A mold shape design device provided with a mold matching shape creation means for creating a partial shape for carrying out, or a cage fixed shape creation means for creating a partial shape for fixing the mold to a cage that suppresses deformation of the mold If a mold shape design apparatus equipped with is used, a highly accurate three-dimensional product can be quickly and easily manufactured while saving the trouble of shape operation.
[0030]
If the flow path forming means for adding the shape of the flow path to the shape of the mold is provided, a three-dimensional product having high strength and rigidity can be quickly and reliably manufactured without the need for shape operation.
[0031]
When the reinforcing material shape creating means for creating the shape of the reinforcing material based on the shape of the target three-dimensional product is provided, it is possible to manufacture a three-dimensional product having particularly high strength and rigidity while saving time and effort of shape operation.
[0032]
When equipped with a temperature controller that keeps the molten easy fusion gold at a temperature 5 to 20 ° C. lower than the softening point of the thermoplastic material, melting while adjusting the temperature of the easy fusion gold so that the mold does not deform by casting. It is possible to manufacture a three-dimensional product simply and safely without the trouble of carrying out.
[0033]
If a temperature controller that keeps the heating fluid at a temperature lower than the softening point of the thermoplastic material and higher than the melting point of the easily fused gold, and a pump that discharges the heating fluid into the flow path, a reinforcing material is provided. Therefore, it is possible to easily and reliably manufacture a three-dimensional product having high strength and rigidity by eliminating the trouble of preparing and flowing a liquid for preheating the casting mold.
[0034]
If the heating fluid is polyhydric alcohol or a mixture containing polyhydric alcohol as the main component, the liquid used to preheat the mold does not cause environmental pollution, and a solid product with high strength and rigidity is safe and simple. Can be manufactured reliably.
[0035]
A temperature controller that maintains the heating fluid at a temperature lower than the softening point of the thermoplastic material and higher than the melting point of the easily fused gold, and a pump that discharges the heating fluid or the cooling fluid into the flow path And a valve for switching the discharge of the heating fluid or the cooling fluid to one of the flow paths, a liquid discharge port for preheating the mold, and a liquid discharge for cooling the mold This eliminates the need to reconnect the outlets, and enables the manufacture of highly rigid three-dimensional products that are safe, simple, reliable and quick.
[0036]
Employing a small piece of metal coated with easy fusion gold saves the trouble of preparing a reinforcing material in accordance with the shape of the three-dimensional product, and can quickly and easily produce a three-dimensional product with high rigidity.
[0037]
When the metal is iron or an iron-based alloy, the affinity between the reinforcing material and the easily fused gold is increased, so that a three-dimensional product having high strength and rigidity can be manufactured quickly and easily.
[0038]
If the ratio of the largest dimension to the smallest dimension among the dimensions of the metal pieces measured along three directions orthogonal to each other is three times or more, the filling rate of the reinforcing material with respect to the volume of the mold is increased. Since it increases, a three-dimensional product with higher rigidity can be manufactured.
[0039]
When equipped with a screen that separates the reinforcing material from the meltable fusion metal, the fusion metal can be reused, and a three-dimensional product having high strength and rigidity can be manufactured quickly, simply, and at low cost.
[0040]
The easy-to-use financial solution that also serves as a heated fluid circulation device can reduce the size and price of the required equipment, and can quickly and easily produce a three-dimensional product with high strength and rigidity at a low price.
[0041]
In the easy-to-fuse financial solution that also serves as the easy-to-fuse gold recycling device, the required equipment can be reduced in size and price, and a three-dimensional product with high strength and rigidity can be manufactured quickly, simply, and at low cost.
[0042]
By adopting easy fusion gold containing bismuth and tin as main components, easy fusion gold is less likely to cause environmental pollution, and a three-dimensional product with high strength and rigidity can be manufactured safely, simply and reliably.
[0043]
In addition, if 0.5% to 5% copper or 0.5% to 5% silver is included in the easily fused gold, the material properties of the easily fused gold are improved, and it has high strength and rigidity, and is deformed by creep. Can be manufactured safely, easily and reliably.
[0044]
DETAILED DESCRIPTION OF THE INVENTION
Next, with reference to FIGS. 1-16, the Example of the three-dimensional goods manufacturing method and three-dimensional goods manufacturing apparatus by this invention is demonstrated.
[0045]
Example 1
FIG. 1 is a flowchart showing a processing procedure of a three-dimensional product manufacturing method P according to the present invention. A three-dimensional product manufacturing method P for manufacturing a completed three-dimensional product M3 from CAD data D describing the shape of a target three-dimensional product includes a mold manufacturing process P1, an easy fusion gold casting process P2, and a mold removing process P3. .
[0046]
The mold manufacturing process P1 is a process of making the mold M1 by the SLS method based on the CAD data D. The easy fusion gold casting step P2 is a step of pouring molten easy fusion gold into the mold M1 and then cooling and solidifying it. The mold M1 in which easy-fusion gold is cast is referred to as a cast mold M2. The mold removal process P3 is a process of removing the mold M1 from the cast mold M2 and leaving a finished three-dimensional product M3 made of easy-fusion gold.
[0047]
FIG. 2 is a flowchart showing a more detailed processing procedure of the mold manufacturing process P1. The data receiving step P11 is a step of receiving CAD data D that is a solid model from a connected computer and converting the solid model into surface shape data D1 that is a surface model.
[0048]
The mold shape creation process P12 is a process in which the surface shape data D1 is offset to create the external shape data D2, and these are combined to create the mold shape data D3.
[0049]
The mold shape data D3 is also added with a partial shape such as a mold dividing surface T1 that is necessary for using the molded article W as the mold M1.
[0050]
The SLS modeling process P13 is a process for manufacturing the mold M1 having the shape described by the mold shape data D3 by the SLS method.
[0051]
FIG. 3 is a diagram illustrating the structure of the SLS modeling apparatus A used in the SLS modeling process P13. The SLS modeling apparatus A includes a container A1 that holds the material powder S, a recoater A2 that flattens the surface of the material powder S, a recoater driving device A3 that rotates the feed screw A8 to reciprocate the recoater A2, and the material powder S. A laser head A4 that irradiates the surface with a laser beam, a scanner A5 that scans the laser head A4 back and forth, and right and left, an elevator A6 that supports a material powder S and a modeled article W, and an elevator drive that moves the elevator A6 up and down It is comprised by apparatus A7 and control apparatus A9 which controls operation | movement of the SLS modeling apparatus A entirely.
[0052]
The recoater driving signal X1 is a signal for operating the recoater driving device A3 and supplying power. The scanner / laser drive signal X2 is a signal for controlling the scanning path of the laser head A4 and the blinking of the laser beam to supply electric power. The elevator drive signal X3 is a signal that controls the operation of the elevator A6 and supplies electric power.
[0053]
FIG. 4 is a diagram showing the operation of the SLS modeling apparatus A of FIG. The SLS modeling apparatus A irradiates the surface of the flattened material powder S while scanning the laser beam to sinter the material powder S, and has a cross-sectional shape of the modeled object W described by the mold shape data D3. Make a layer. Then, a large number of layers are stacked to create a shaped object W having a target three-dimensional shape.
[0054]
When receiving the mold shape data D3, the control device A9 generates the three-dimensional data having the three-dimensional shape of the modeled object W based on the data D3. Next, in order to laminate, the intersection of this three-dimensional data and the horizontal plane at the height of each layer is calculated, the cross-sectional shape of the modeled object W is calculated, and for each layer, the recoater drive signal X1, scanner, laser drive Signal X2 and elevator drive signal X3 are automatically generated.
[0055]
With these drive signals, the SLS modeling apparatus A places the material powder S on the elevator A6 or the modeled object W, reciprocates the recoater A2, and flattens the surface of the material powder S. The surface of the material powder S is irradiated with a laser beam from the laser head A4.
[0056]
The scanner A5 scans the laser head A4 along the cross section of the modeled object W. The material powder S is sintered by the laser beam to form a thin layer.
[0057]
The elevator A6 is lowered by the thickness of one layer, and is prepared for stacking a new layer on the model W.
[0058]
By such an operation, a mold M1 is finally made.
[0059]
The commercially available SLS modeling apparatus A uses nylon powder as the material powder S. Nylon, which is a highly crystalline polymer, has a sharp softening point that can be regarded as a melting point, and its temperature is about 190 ° C. Since this softening point temperature is sufficiently high with respect to the melting point of the easily fused gold which is 160 ° C. or less, it can be used as a mold for casting the easily fused gold as the molded article W.
[0060]
FIG. 5 is a flowchart showing a method for realizing the easy fusion casting process P2. The mold cleaning process P21 is a process for removing the material powder S remaining inside the mold M1 and the material powder S adhering to the mold M1 to produce a cleaned mold M11.
[0061]
The mold smoothing process P22 is a process of smoothing a step appearing on the surface of the cleaned mold M11 when the mold M1 is laminated and manufactured by polishing or painting.
[0062]
The easy fusion gold melting step P23 is a step of heating and melting the easy fusion gold F so as not to exceed the melting point of the material of the mold M1 to provide the easy fusion gold melt F1.
[0063]
FIG. 6 is a chart showing an example of the composition of easy-to-use gold F that can be used. Among these easily fused gold F, those containing cadmium and lead are difficult to use, so bismuth, tin eutectic alloys and the like having a melting point of 138 ° C. are practical materials. Since the melting point of the easy fusion gold F is low, a large-scale casting facility is unnecessary. The easy fusion gold casting step P24 is a step of casting the easy fusion gold melt F1 into the cleaned mold M11 to make an unsolidified mold M12.
[0064]
The easy fusion gold cooling step P25 is a step of cooling the unsolidified mold M12 and solidifying the cast easy fusion gold melt F1 to produce a cast mold M2.
[0065]
FIG. 7 is a diagram showing the mold removing step P3. The cast product smoothing step P33 is a step of smoothing the surface of the cast product M21 by polishing or painting to obtain a finished three-dimensional product M3.
[0066]
The mold splitting process P31 is a process of dividing the mold M1 surrounding the cast mold M2 by a mold dividing surface and taking out the cast product M21.
[0067]
The die cutting process P32 is a process of removing the divided mold M1 from the casting M21 stuck in the mold M1. Depending on the shape of the casting M21 and the mold dividing surface T1, the mold M1 may not easily come off from the casting M21. In such a case, a die cutting process P32 is required in addition to the mold splitting process P31.
[0068]
According to such a three-dimensional product manufacturing method P, a completed three-dimensional product M3 made of easy-to-fuse gold F is produced. The strength of the easily fused gold F expressed by tensile strength is about 60 MPa, and the rigidity expressed by Young's modulus is about 30 GPa. When these values are compared with nylon used in a commercially available SLS modeling apparatus, the strength is about 3 times and the rigidity is about 15 times.
[0069]
The finished three-dimensional product M3 made of the easily fused gold F can be easily smoothed by polishing and painting. Further, the three-dimensional product manufacturing method P does not include a process that requires large-scale equipment. Therefore, when the three-dimensional product manufacturing method P is used, rapid prototyping can be used to quickly and easily manufacture a three-dimensional product having not only high strength and rigidity but also excellent accuracy and surface roughness.
[0070]
Next, the three-dimensional product manufacturing method P will be described in detail with an example. In this example, a figurine used as an interior is created. The solid cedar shape is described by CAD data D prepared in advance.
[0071]
In the data reception process P11, the CAD data D is converted into a surface model to create surface shape data D1. FIG. 8A schematically shows the surface shape R1 described by the surface shape data D1.
[0072]
In the mold shape creation step P12, the outer shape data D2 is created by offsetting the surface shape data D1 to the outside. FIG. 8B is a diagram schematically showing the outer shape R2 described by the outer shape data D2. Further, the surface shape R1 is subtracted from the outer shape R2 to form a shell shape having a substantially uniform thickness. If the thickness of the mold M1 is made uniform, deformation of the mold M1 caused by a temperature change during casting can be minimized.
[0073]
Various partial shapes necessary for using the modeled object W as the mold M1 are added to the shell shape thus created to create a mold shape R3. The partial shape includes a mold dividing surface T1 for dividing the mold M1 into a plurality of pieces, a bit pin T2 for aligning the position of the mold M1, a support leg T3 for holding the mold M1 vertically, and an easy fusion gold fusion to the mold M1. The spout T4 for pouring the material F1, the air vent T5 for replacing the air in the mold M1 with the easily fused gold melt F1, the clipping point T6 for assembling the divided mold M1 with clip fittings, and the deformation of the mold M1 A fixing leg T7 for attaching to a fixing metal fitting for suppressing the above, a flow path T8 for flowing a liquid for heating or cooling the mold M1, and the like are included. FIG. 8C shows the mold shape R3 described by the mold shape R3 data.
[0074]
The shape operation for creating the mold shape R from the CAD data D is usually performed manually by a CAD operator. In order to support this, Modeler C is prepared as dedicated CAD software. The modeler C automatically or extremely performs operations for offsetting the surface shape R1 to create the outer shape data D2 and the shell shape, determining the mold dividing surface T1, and adding various partial shapes to the shell shape. It has commands to make it easy.
[0075]
FIG. 9 is a diagram illustrating an example of the modeler C screen. The command of the modeler C is registered in the menu C1, and the CAD operator can execute a complicated shape operation with a simple operation using these commands. For example, the “outer shape” command is a command for generating a new three-dimensional shape by offsetting the selected three-dimensional shape to the outside.
[0076]
Therefore, if the “outer shape” command is executed after selecting the surface shape R1, the outer shape R2 can be easily created. If the “shell shape” command is executed after selecting the outer shape R2 and the surface shape R1, the shape can be easily created. Furthermore, if a reference point Q is set on the surface of the shell shape as shown in the screen, and then the “pouring gate” command is executed, the pouring gate T4 is added thereto.
[0077]
In the SLS modeling process P13, the mold shape data D3 is transmitted to the commercially available SLS modeling apparatus A, and the molded object W having the mold shape R3 as a three-dimensional shape, that is, the mold M1 is created.
[0078]
In the mold cleaning process P21, the mold M1 is inverted and vibrated, and the material powder S clogged in the mold M1 is dropped. The material powder S adhering to the inner surface of the mold M1 is removed by inserting a thin rubber tube into the mold M1 and blowing air from its end face. In this way, a cleaned mold M11 is made.
[0079]
In the mold smoothing step P22, the inner surface of the cleaned mold M11 is smoothed to a predetermined surface roughness. As a smoothing method, there are a polishing method that removes the convex portion of the step using a paper file, a coating method that fills the concave portion of the step using a filling paint, and a method that uses both of them.
[0080]
In the easy fusion gold melting step P23, it is convenient to use a dedicated electric furnace H in order to melt the easy fusion gold F and keep it at an appropriate temperature.
[0081]
FIG. 10 is a diagram showing the structure of the electric furnace H. The crucible H1 contains a bismuth-tin eutectic alloy having a melting point of 138 ° C., and is melted by the heat generated by the heater H3 to form an easily fused gold melt F1. The easily fused gold melt F1 is easily oxidized by oxygen in the air when heated. Therefore, the glycerin bath H2 is used and the crucible H1 is indirectly heated to prevent overheating of the easily fused gold melt F1.
[0082]
A thermostat H4 for controlling energization to the heater H3 is attached to the glycerin bath H2. When the temperature of glycerin exceeds a predetermined set temperature due to the heat generated by the heater H3, the thermostat H4 operates to stop energizing the heater H3. The temperature of the glycerin bath H2 and the easily fused gold melt F1 is maintained at the set temperature of the thermostat H4. The optimum set temperature of the thermostat H4 varies depending on the material of the mold M1. Usually, the temperature is set 5 to 20 ° C. lower than the softening point. Instead of glycerin, a polyhydric alcohol such as ethylene glycol may be employed.
[0083]
When nylon is used as the material powder S, the set temperature may be set to 185 ° C. considering that the softening point is about 190 ° C. Nylon has a sharp softening point, so it hardly softens even at 185 ° C.
[0084]
Note that the spout H5 of the electric furnace H is attached to the bottom of the crucible H1, so that the oxide floating on the surface of the easily fused gold melt F1 does not flow into the mold M1 from the spout H5. ing.
[0085]
In the easy-fusion gold casting step P24, first, the cleaned mold M11 divided into a plurality of parts is assembled by attaching the clip metal fitting J3 to the clipping point T6, and the support leg T3 is fixed to the base metal fitting J1 and supported vertically. . Further, a fixing leg T7 is attached to the fixing metal fitting J2 attached to the base metal fitting J1, and deformation of the mold M1 due to casting is suppressed. This is placed so that the sprue T4 comes directly below the spout H5 of the electric furnace H, and the easy fusion metal F is poured from above.
[0086]
In the easy fusion gold cooling step P25, the unsolidified mold M12 is allowed to cool for a while to solidify the easy fusion gold melt F1. FIG. 11 is a diagram showing the structure of the cast mold M2 thus produced.
[0087]
In the mold splitting process P31, the casting M21 is taken out by a method in which the mold I1 is inserted in the gap of the mold M1 surrounding the cast mold M2 and twisted to remove the divided mold M1. When nylon is used as the material of the mold M1, it is not necessary to use a release agent or the like because the affinity between the nylon and the easily fused gold F is very small.
[0088]
However, depending on the shape of the cast product M21 and the mold dividing surface T1, the cast product M21 may get stuck in the divided mold M1 and may be difficult to take out. In the die-cutting process P32, the mold M1 is held so that the cast product M21 that is stuck is facing upward, and the portion of the mold M1 around the cast product M21 is hit with a hammer I2. If it does in this way, the casting M21 will come out from the casting_mold | template M1 due to the difference in the density of nylon and the easy-to-fuse gold F.
[0089]
Nylon, which is the material of the mold M1, is not easily broken against impact and vibration, but slightly elastically deforms when a large force is applied. Therefore, in many cases, this method can be used to separate the casting M21 from the mold M1 without breaking it. FIG. 12 is a diagram illustrating operations performed in the mold splitting process P31 and the mold cutting process P32.
[0090]
In the casting smoothing step P33, the surface of the casting M21 is smoothed to a predetermined surface roughness by polishing or painting. Even in the mold smoothing step P22, the inner surface of the mold M1 is smoothed, but it is difficult to sufficiently smooth the concave portion of the mold M1 that is difficult to reach.
[0091]
However, since the concave portion of the mold M1 becomes a convex portion of the cast product M21 by casting, the concave portion that has not been sufficiently smoothed in the mold smoothing step P22 is sufficiently polished and painted in the cast product smoothing step P33. Can be smoothed. By combining the mold smoothing step P22 and the cast product smoothing step P33 as described above, the entire surface of the cast product M21 can be sufficiently smoothed.
[0092]
The mold M1 removed in the mold splitting process P31 and the mold cutting process P32 can be used repeatedly 10 times or more. This ability to be used repeatedly is one of the features of the present invention. Therefore, when making a plurality of finished solid objects M3, if as many parts of the surface of the mold M1 as possible are smoothed in the mold smoothing step P22, the number of finished solid objects M3 must be smooth. The process P33 can be labor-saving.
[0093]
Example 2
If beads of an inorganic material such as glass are mixed with the material powder S, the strength and rigidity of the mold M1 can be increased, and deformation during casting can be suppressed. Further, the thickness of the mold M1 can be reduced, and heat can be easily radiated. This shortens the time for cooling the unsolidified mold M12 in the easy fusion gold cooling step P25, and the completed three-dimensional object M3 is obtained more quickly.
[0094]
In addition, if beads made of a material having a high thermal conductivity such as metal are used, the time for cooling the unsolidified mold M12 can be further shortened.
[0095]
Example 3
When forming the mold M1 in the mold manufacturing process P1, if a flow path for heat exchange is formed inside the mold M1, the flow of the unsolidified mold M12 in the easy fusion cooling process P25 is accelerated. A cooling liquid can flow through the passage. Unlike the method of reducing the thickness of the mold M1, this method can freely control the solidification time of the easily fused gold melt F1. Therefore, the casting M21 having a complicated shape can be accurately produced. Moreover, since the easily fused gold melt F1 can be rapidly solidified, the crystals of the easily fused gold F used as the material of the casting M21 become finer, and the material characteristics of the casting M21 are improved.
[0096]
Further, as a method for further increasing the strength and rigidity of the finished three-dimensional product M3, there is a method in which a reinforcing material is made of a metal having a melting point higher than that of the easily fusible metal F and placed in the mold M1 in advance before casting. However, in this method, when the ratio of the volume of the reinforcing material to the volume of the mold M1 is large, the cast easily fused gold melt F1 is cooled in contact with the normal temperature reinforcing material and solidifies unevenly. Therefore, casting is not performed well.
[0097]
For this, a method in which the reinforcing material and the mold M1 are preheated to a temperature higher than the melting point of the easy fusion metal F in advance is effective. Also in this case, if the flow path is formed inside the mold M1, the mold M1 can be preheated by flowing a heating liquid through the flow path before casting the easily fused gold melt F1.
[0098]
In order to support a shape operation for forming a flow path inside the mold M1, a dedicated “flow path” command is registered in the modeler C used in the mold shape creation step P12. This command defines an intermediate surface between the inner surface and the outer surface of the mold M1 so that the ratio of the distance to the inner surface and the distance to the outer surface is constant, and generates a flow path T8 along the intermediate surface. Also, joints are provided at the inlet and outlet of the flow path T8 so that tubes can be connected.
[0099]
It is convenient to use the liquid circulation device G in order to flow the cooling or heating liquid through the flow path formed inside the mold M1.
[0100]
FIG. 13 is a diagram showing the structure of the liquid circulation device G. The liquid circulation device G includes both a high-temperature glycerin tank G1 that supplies high-temperature glycerin heated by the heater H3 and a normal-temperature glycerin tank G2 that supplies normal-temperature glycerin. Like the electric furnace H, the high-temperature glycerin tank G1 is provided with a heater H3 and a thermostat H4, and the temperature of glycerin is maintained at about 185 ° C.
[0101]
The pump G3 discharges high temperature or normal temperature glycerin to the discharge port G5. The temperature of the discharged glycerin can be switched by operating the valve G4. That is, according to the purpose of using the liquid circulation device G, when pre-heating the mold M1 in the easy-fusion gold casting step P24, high-temperature glycerin is discharged, and when cooling the unsolidified mold M12 in the easy-fusion gold cooling step P25. Switches the valve G4 so that normal temperature glycerin is discharged. The liquid circulation device G may be configured to also serve as the electric furnace H. In this case, the glycerin bath H2 of the electric furnace H is used as the high-temperature glycerin tank G1 of the liquid circulation device G.
[0102]
There are several ways to make a reinforcement that will be placed inside the mold M1 before casting.
[0103]
One method is a method in which a large number of small pieces of steel are prepared, and this is covered with an easy-to-fuse gold F to form a reinforcing material. Iron-based metals such as steel are particularly suitable for use as reinforcing materials because they have a strong affinity with the easily fused gold F. This reinforcing material can be made in large quantities in advance and used as much as necessary. The reinforcing material of the steel piece is effective in improving the rigidity of the finished three-dimensional object M3, but the strength is not improved so much because the reinforcing materials are not in contact with each other.
[0104]
When the filling rate of the reinforcing material with respect to the volume of the mold M1 is increased, the rigidity can be further improved. The filling rate of the spherical small pieces is about 50%, but the filling rate can be increased to 70% or more by using a piece-like or rod-like small piece and further filling while vibrating. According to the inventors' experiment, when the ratio of the largest dimension to the smallest dimension among the dimensions of the metal piece measured along three directions orthogonal to each other is three times or more, the mold Since the filling rate of the reinforcing material with respect to the volume increases, a three-dimensional product with higher rigidity can be manufactured.
[0105]
Another method is an SLS method in which a metal powder such as stainless steel is used as the material powder S, and is a method of making a reinforcing material having an optimum shape based on the shape of the completed three-dimensional object M3. In the SLS method using the metal powder as the material powder S, generally, the shaped object W is made porous. Therefore, there is already a method in which a metal such as bronze is infiltrated into this and the pores of the shaped object W are filled to increase the strength. It has been put into practical use. If this method is used, since the filling rate of the reinforcing material with respect to the volume of the mold M1 can be increased, the strength and rigidity of the completed three-dimensional object M3 can be greatly improved at the same time. The SLS method using the metal powder as the material powder S has drawbacks such as a long modeling time and poor accuracy. However, when the model W is used as a reinforcing material, it can be used without any particular problem.
[0106]
FIG. 14 is a diagram illustrating an example in which a reinforcing material made by the SLS method is used. The shape of the reinforcing material J4 can be created by offsetting the surface shape R1 inward. That is, it is possible to simultaneously create the outer shape R2 and the shape of the reinforcing material J14 in the mold shape creation step P12.
[0107]
The completed three-dimensional object M3 that has become unnecessary can be melted to regenerate the easily fused gold F. In this case, in order to separate the reinforcing material mixed in the easy fusion money F, it is convenient to use a dedicated easy fusion money reproducing device U. FIG. 15 is a diagram illustrating the structure of the easy-to-fuse money reproducing apparatus U.
[0108]
The easily fused gold recycling apparatus U includes a screen U1 having many small holes, and separates the easily fused gold melt F1 and the reinforcing material. The screen U1 is heated to a temperature equal to or higher than the melting point of the easily fused gold F by the heater U2. When the completed three-dimensional object M3 is placed on the screen U1, the completed three-dimensional object M3 is melted by the heat transmitted from the screen U1, and is changed to an easily fused gold melt F1 including a reinforcing material. Among them, only the easily fused gold melt F1 falls from the small hole of the screen U1, and is cooled by the water tank U3 to become the solid easily fused gold F.
[0109]
The easily fused gold recycling apparatus U may also be configured to serve as the electric furnace H. In this case, the crucible H1 of the electric furnace H is placed in place of the water tank U3 of the easy-fusion regenerator U. FIG. 16 is a diagram showing the structure of the easily fused gold recycling apparatus U configured to serve also as the electric furnace H.
[0110]
Example 4
In the mold manufacturing process P1, instead of using the SLS modeling apparatus A, it is also possible to use a layered modeling apparatus of another method such as an optical modeling apparatus or an FDM modeling apparatus.
[0111]
For example, in an optical modeling apparatus, shape data in a computer is cut along horizontal planes at equal intervals in the height direction to create slice figures. Next, slice graphic data is sequentially extracted from the lower end, and based on the shape, a light beam, for example, is applied to a photocurable resin to form a solidified layer. After forming the solidified layer of one layer, the stage on which the photocurable resin is mounted is relatively lowered, and the uncured resin layer having the same interval thickness is overlaid thereon, and this is sequentially extended to the upper end. Repeat the operation. As a result, a desired template is obtained.
[0112]
Example 5
As the easily fused gold F, instead of using a bismuth-tin eutectic alloy, a material to which 0.5% to 5% copper or 0.5% to 5% silver is added can also be used. A material to which about 2% copper or silver is added is preferable. Bismuth and tin eutectic alloys have problems in that they are low in strength and rigidity among practical metal materials, and creep is likely to increase in proportion to time even with a small force. .
[0113]
However, when copper or silver is added to the easily fused gold F, the crystals become finer, so that strength and rigidity are increased and creep is also suppressed. The melting point will be somewhat higher but not a problem. If copper or silver exceeds 5%, the melting point becomes too high, whereas if it is less than 0.5%, the material properties are not improved.
[0114]
【The invention's effect】
According to the present invention, a mold is made of a thermoplastic material, and an easily fused gold melted at a temperature lower than the softening point of the thermoplastic material is poured into the mold to be solidified into a cast product. Therefore, rapid prototyping is utilized. Thus, it is possible to quickly and easily manufacture a three-dimensional product having high strength and rigidity, as well as excellent accuracy and surface roughness.
[0115]
At this time, since no equipment that becomes hot is used, a three-dimensional product made of metal can be easily manufactured even in a closed work environment such as a design office.
[0116]
Since the mold can be used repeatedly more than 10 times, when making a plurality of finished solid objects, if the surface of the mold is smoothed as much as possible in the mold smoothing step, the number of finished solid objects must be as many as possible. It is possible to save labor in the casting smoothing process.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a processing procedure of a three-dimensional product manufacturing method P according to the present invention.
FIG. 2 is a flowchart showing a more detailed processing procedure of a mold manufacturing process P1.
FIG. 3 is a diagram showing a structure of an SLS modeling apparatus A used in an SLS modeling process P13.
FIG. 4 is a diagram illustrating an operation of the SLS modeling apparatus A of FIG.
FIG. 5 is a flowchart showing a method of realizing the easy fusion gold casting step P2.
FIG. 6 is a chart showing an example of the composition of easy-to-use gold F that can be used.
FIG. 7 is a diagram showing a mold removing step P3.
FIG. 8 is a diagram showing a surface shape R1, an outer shape R2, and a mold shape R3.
FIG. 9 is a diagram illustrating an example of a modeler C screen;
10 is a view showing a structure of an electric furnace H. FIG.
FIG. 11 is a diagram showing the structure of a pre-made mold M2.
FIG. 12 is a diagram showing operations performed in a mold splitting process P31 and a mold cutting process P32.
13 is a view showing a structure of a liquid circulation device G. FIG.
FIG. 14 is a diagram showing an example in which a reinforcing material made by the SLS method is used.
FIG. 15 is a diagram showing a structure of the easy-to-fuse money reproducing apparatus U.
FIG. 16 is a diagram showing a structure of an easily fused gold recycling apparatus U configured to also serve as an electric furnace H.
[Explanation of symbols]
A selective laser sintering (SLS) modeling equipment
A1 container
A2 Recoater
A3 Recoater drive
A4 laser head
A5 scanner
A6 elevator
A7 Elevator drive device
A8 Lead screw
A9 Control device
C Modeler
C1 menu
D CAD data
D1 Surface shape data
D2 Outline shape data
D3 Mold shape data
F easy fusion money
F1 Fused gold melt
G Liquid circulation device
G1 High temperature glycerin tank
G2 room temperature glycerin tank
G3 pump
G4 valve
G5 outlet
H Electric furnace
H1 crucible
H2 Glycerin bath
H3 heater
H4 thermostat
H5 outlet
I1 leverage
I2 hammer
J1 mounting bracket
J2 Fixing bracket
J3 clip metal fittings
J4 reinforcement
M1 mold
M11 Cleaned mold
M12 Unsolidified mold
M2 cast mold
M21 casting
M3 finished solid product
P Three-dimensional product manufacturing method
P1 mold manufacturing process
P11 data reception process
P12 Mold shape creation process
P13 SLS modeling process
P2 easy fusion gold casting process
P21 Mold cleaning process
P22 Mold smoothing process
P23 Fused gold dissolution process
P24 Easy fusion gold casting process
P25 Easy fusion gold cooling process
P3 mold removal process
P31 parting process
P32 die cutting process
P33 Casting smoothing process
Q reference point
R1 surface shape
R2 external shape
R3 mold shape
S material powder
U easy-to-use gold recycling device
U1 screen
U2 heater
U3 water tank
T1 type dividing surface
T2 bit pin
T3 support leg
T4 Yuguchi
T5 air handling
T6 clipping point
T7 fixed leg
T8 channel
W Modeling
X1 Recoater drive signal
X2 Scanner laser drive signal
X3 Elevator drive signal
Z Rapid Prototyping Peripheral Device

Claims (3)

A mold manufacturing process for making a mold with a thermoplastic material;
An easy-fusion gold casting step in which an easy-fusion gold melted at a temperature lower than the softening point of the thermoplastic material is poured into the mold to be solidified into a cast product, and
In the mold shape design apparatus for supporting the mold shape created in including standing body article manufacturing method and a mold removal step of removing the removable the casting by dividing the mold as the target of the three-dimensional article,
An apparatus for designing a mold shape, comprising offset mold creating means for offsetting all or a part of the shape of the target three-dimensional product outward to create an outer shape of the mold . In the mold shape design apparatus for supporting your Keru the mold shape created stereoscopic article manufacturing method according to claim 1,
A mold shape design apparatus comprising a mold alignment shape creation means for creating a partial shape for mutually aligning the plurality of divided molds . In the mold shape design apparatus for supporting your Keru the mold shape created stereoscopic article manufacturing method according to claim 1,
A mold shape design apparatus comprising: a cage fixing shape creating means for creating a partial shape for fixing the mold to a cage for suppressing deformation of the mold .

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